An ultraviolet light source is a well known means for sanitizing and disinfecting many targeted objects to include fluids. When administered at the desired frequencies, durations, and intensities, ultraviolet (UV) light is able to kill a wide array of micro-organisms that include, but not limited to, bacteria, viruses, spores, algae and protozoa, without having to chemically treat the object to be disinfected. One type of common UV bulb includes a quartz or glass casing that holds a vaporizable material, such as mercury, and also holds a stabilizing gas. The stabilizing gas may be one of the noble gases such as argon, neon, or xenon. An electrode positioned within the area sealed by the casing excites the stabilizing gas and vaporizable material. Ultraviolet light is emitted from a plasma field which is generated with the excited vaporizable material.
The ability of a UV light source to disinfect an object is primarily a function of exposure time and intensity of the exposure. For purposes of disinfecting or sanitizing a targeted object, it is therefore advantageous to use a source of UV light that consumes a minimum amount of power, yet produces an intense UV light output.
One of the more common types of UV light sources that are used as sanitizing/disinfecting agents are low pressure mercury lamps. Low pressure mercury lamps are generally cost effective in that their power requirements are low as compared to other types of UV light sources, yet low pressure mercury lamps also have a comparatively high UV output. One disadvantage with mercury lamps is that they are unable to adequately function in temperatures that fall outside optimal operating temperatures of the mercury lamps. UV light sources have been proven to be effective in sanitizing and disinfecting freezers/coolers used in the food handling industry; however, degradation in the performance of the UV light sources is experienced due to the colder temperatures that fall well below the optimal operating temperatures of the UV light sources. Low pressure mercury lamps are most efficient in producing ultraviolet light when the lamps are maintained at a temperature between about 80° to 90° F.
Therefore, it is apparent that a cost effective means is needed for providing UV disinfection/sanitization, particularly in those industries where ambient temperatures of objects to be sanitized are well below the optimal operating temperature ranges of a UV light source.
Also, there are circumstances when a UV light source may be subjected to temperatures that exceed optimal operating temperatures; thus, there is also a need to provide UV disinfection/sterilization in these conditions.
U.S. Patent Application Publication No. U.S. 2003/0001112 discloses a hermetically sealed ultraviolet light source in the form of an ultraviolet light bulb/lamp and a protective sleeve that surrounds the ultraviolet bulb. The sleeve helps to insulate the ultraviolet bulb which therefore helps to keep the bulb's plasma thermally stable.
U.S. Patent Application Publication No. 2003/00038247 discloses a watertight irradiation apparatus utilizing a microwave excited ultraviolet radiation generator that includes an electrodeless lamp. The UV radiation generator is enclosed within a watertight housing having an irradiation window allowing the UV rays to pass from the lamp to a target area.
While the prior art may suggest use of a covering to protect an otherwise exposed ultraviolet light source, a need still exists for providing an ultraviolet light source that may be selectively and controllably heated or cooled to optimize the output of the ultraviolet light source, regardless of the temperature at which the source is exposed to during use.